AURORAS: A coronal mass ejection that left the Sun on August 14th could buffet Earth's magnetic field on August 15th or 16th. Sky watchers at high latitudes (e.g., Canada, New Zealand and the northern tier of US states) should be alert for auroras especially during the hours around local midnight on Thursday and Friday.

AN ASTEROID: Asteroids are usually hard to see, but you can spot one this weekend using only a small telescope or good binoculars. The unusualy bright space rock, 2002 NY40, will glide by Earth on August 17th and 18th only a little farther from our planet than the Moon. (There's no danger of a collision.) Visit spaceweather.com for links to sky maps and observing tips.

A SUNSPOT: Who said solar max is over? The Sun is once again peppered with spots. The largest, active region 69, is truly impressive. It spans an area seven times greater than the surface area of Earth and poses a threat for powerful flares. The big spot is easy to see from Earth--but never stare directly at the Sun! Instead, use safe solar projection methods described at http://www.spaceweather.com.